Michu seeing the important part which the state of his clothes was likely to play, invented this subterfuge.

If, in law, truth is often like falsehood, falsehood on the other hand has a very great resemblance to truth.
The defence and the prosecution both attached much importance to this testimony, which became one of the leading points of the trial on account of the vigor of the defence and the suspicions of the prosecution.
Gothard, instructed no doubt by Monsieur de Grandville, for up to that time he had only wept when they questioned him, admitted that Michu had told him to carry the plaster.
"Why did neither you nor Gothard take the justice of peace and the forester to the stone post and show them your work ?" said the public prosecutor, addressing Michu.
"Because," replied the man, "I didn't believe there was any serious accusation against us." All the prisoners except Gothard were now removed from the courtroom.
When Gothard was left alone the president adjured him to speak the truth for his own sake, pointing out that his pretended idiocy had come to an end; none of the jurors believed him imbecile; if he refused to answer the court he ran the risk of serious penalty; whereas by telling the truth at once he would probably be released.

Gothard wept, hesitated, and finally ended by saying that Michu had told him to carry several sacks of plaster; but that each time he had met him near the farm.

He was asked how many sacks he had carried.
"Three," he replied.
An argument hereupon ensued as to whether the three sacks included the one which Gothard was carrying at the time of the arrest (which reduced the number of the other sacks to two) or whether there were three without the last.

The debate ended in favor of the first proposition, the jury considering that only two sacks had been used.